Jasperre: kivi found that the module will load after another (recognized) file, such as a 2da, is added to the hak. Once this is done, the custom contextmenu.xml is not recognized.
Which ties in well with my thoughts on custom content:
While specific uses may vary, there needs to be consistency. Every single resource type should load uniformly whether contained in a Hak, Override folder, or a Campaign folder. This includes gui xml, tga, dds, mdb, wav, ncs, nss, ut*, sef, pfx, bbx, and all the other myriad file types that NWN recognizes as resources.